1. Field
This application generally relates to the field of wireless communication systems, and more particularly to establishing communication parameters for access terminals used in such systems.
2. Related Art
Subject matter set forth herein is applicable to wireless communication systems generally. However, it has been developed in the context of CDMA cellular telecommunication systems that provide high-speed connectivity including data and voice transport on both point-to-point and point-to-multipoint bases. First-generation (analog) and second-generation (digital) cellular networks were used primarily for communicating voice traffic via mobile cellular telephones, and thus maintained a focus on access methods for the efficient transport of voice information. With the rising popularity of the Internet, a third-generation (3G) wideband multimedia cellular network continues to be developed to transport both voice and data at much higher speeds than were available using the first and second generation wireless networks.
Wireless Communication Standards Related to the Present Disclosure
A Third Generation Partnership Project 2 (3GPP2) has been established by industry groups for the purpose of defining specifications to transition current code-division multiple-access (CDMA) wireless networks to the third generation, which is commonly referred to as “cdma2000”. The 3GPP2 is primarily concerned with defining specifications for CDMA systems such as are implemented in North America. A document specifying a somewhat different CDMA system, such as is used more commonly in Europe, may be identified as 3GPP TSG-RAN Release-5, and is hereby incorporated by reference for its teachings on CDMA systems. Also incorporated by reference is so much of 3GPP TSG-RAN Release-6 as has been made public, particularly including documents submitted in conjunction therewith and identified as R1-031268, R1-040534, and R1-040758.
As described in a document entitled “Introduction to cdma2000 Standards for Spread Spectrum Systems”, available from the 3GPP2 in a document number C.S0001-D, published by the 3GPP2 in Feb. 2004, the “cdma2000 family of specifications” specifies a spread spectrum radio interface that uses well known Code Division Multiple Access (CDMA) wireless transmission techniques in order to meet the requirements for 3G wireless communications. The C.S0001-D document is incorporated by reference herein in its entirety. As described in the incorporated C.S0001-D reference, the cdma2000 family of standards includes specifications for the following aspects of the cdma2000 third generation wireless communication system: core air interface, minimum performance, and service standards. The cdma2000 core air interface standards are publicly available from the 3GPP2 as follows: C.S0001-D, Introduction to cdma2000 Standards for Spread Spectrum Systems, February 2004; C.S0002-D, Physical Layer Standard for cdma2000 Spread Spectrum Systems, February, 2004; C.S0003-D, Medium Access Control (MAC) Standard for cdma2000 Spread Spectrum Systems, February, 2004; C.S0004-D, Signaling Link Access Control (LAC) Standard for cdma2000 Spread Spectrum systems, February, 2004; and C.S0005-D, Upper Layer (Layer 3) Signaling Standard for cdma2000Spread Spectrum Systems, February, 2004. In addition, the family includes a standard that specifies analog operation, to support dual-mode mobile stations and base stations. This standard is publicly available from the 3GPP2 as document number C.S0006-D, Analog Signaling Standard for cdma2000 Spread Spectrum Systems, February, 2004. All of the above standards are collectively referred to herein as the “cdma2000 family of standards”, and are hereby incorporated herein as though set forth in full for their teachings on cdma2000 standards.
The cdma2000 family of standards allows seamless evolution from cdma2000 1x systems to cdma2000 “1xEV-DO” (1x Evolution, Data Only or Data-Optimized”) and CDMA2000 1xEV-DV (1x Evolution, Data and Voice) systems. The first phase of cdma2000, cdma2000 1x systems enabled operators with existing IS-95 systems to double overall system capacity. These systems offer 3G type services at speeds up to 140 kbps peak data rate while occupying a very small amount of frequency spectrum (1.25 MHz per carrier). The cdma2000 1x systems are designed for increased voice capacity and support “always-on” data transmission of approximately 153.6 kbps on both the forward and reverse links. The cdma2000 1x systems were first deployed in October, 2000.
In 2004, the cdma2000 1xEV-DO Revision A (or “RevA”) specification was approved by the 3GPP2 Technical Specification Group. Revision A is optimized for packet data service, and supports peak data rates of 3.1 Mbps on the forward link and up to 1.8 Mbps on the reverse link. The high data rates on the reverse link and low data latency enable operators to deliver rich multimedia services, such as video telephony, and enhance user experience. Revision A is an enhanced version of 1xEV-DO Release 0 (or “Rev0”), which delivers up to 2.4 Mbps data speeds and has been commercially deployed since 2002. These systems are also referred to by the 3GPP2 as High Rate Packet Data systems, or “HRPD” systems, in the developing cdma2000 family of standards. Standards defining these HRPD systems are available from the 3GPP2.
For example, the standard defining the 1xEV-DO Rev0 HRPD system is set forth in 3GPP2 document number C.S0024-0 (Versions “V 2.0”, “V 3.0” and “V4.0”) entitled cdma2000 High Rate Packet Data Air Interface Specification, dated Oct. 27, 2000 (for Version V 2.0), Dec. 5, 2001 (for Version V 3.0), and Oct. 25, 2002 (for Version V 4.0). The standard defining the 1xEV-DO RevA HRPD system is set forth in 3GPP2 document number C.S0024-A (Versions 1.0 and 2.0, dated March 2004 and July 2005, respectively), also entitled “cdma2000 High Rate Packet Data Air Interface Specification”. Both of these standards include technical requirements for providing compatibility with cdma2000 HRPD systems. These standards set forth technical requirements that ensure that a compliant Access Terminal (“AT”) can obtain service through any access network that conforms to the standards. All of the HRPD air interface specifications set forth above are hereby incorporated by reference herein as though set forth in full.
In addition to the HRPD standards cited above, 3GPP2 document numbers A.S0007-0 (version V 1.0), A.S0007-0 (version V 2.0), A.S0007-A (versions V 1.0 and V 2.0) and A.S0008-0 (version V 3.0) all describe an inter-operability specification for a Radio Access Network (RAN) that supports HRPD. These specifications contain message procedures and formats necessary to obtain interoperability. Document numbers A.S0007-A (version V 2.0), entitled Interoperability Specification (IOS) for High Rate Packet Data (HRPD) Access Network Interfaces—Rev A, Revision A (Post SDO Ballot, Pre-SDO Publication Version), dated May, 2003 (TIA-1878), and A.S0008-0 (Version V 3.0), entitled Interoperability Specification (IOS) for High Rate Packet Data (HRPD) Access Network Interfaces—Revision 0 (Post SDO Ballot, Pre-SDO Publication Version), dated May 2003, (TIA-878-1) supersede the standards noted above. All of the HRPD interoperability specifications set forth above are hereby incorporated by reference herein as though set forth in full.
The specification that is the most relevant to the advances set forth herein may be identified as either 1xEV-DO Rel. B, and the same specification may also be identified as IS-856-Rel. B. This specification, however nominated, and other standards related to cdma2000 compatible HRPD systems, should be publicly available from the 3GPP2, and are all incorporated by reference herein in their entireties. 3GPP2 document number C.S0054-0, Version V 2.0, entitled CDMA2000 High Rate Broadcast-Multicast Packet Data Air Interface Specification, dated July, 2005, sets forth technical requirements that form the compatibility standard for cdma2000 broadcast high rate packet data systems. These technical requirements ensure that a compliant access terminal (AT) can obtain service through any access network conforming to the standard. The C.S0054-0, Version V 2.0 document is also hereby incorporated by reference herein as though set forth in full.
As is well known, the use of automatic retransmission protocols that operate within a “physical” communication layer, such as the Hybrid Automatic Retransmission reQuest (H-ARQ) protocols, may enhance the efficiency of wireless data transmissions such as those defined by the HRPD specifications cited above. When a transmitting station (TS) transmits a packet to a receiving station (RS), H-ARQ procedures generally require the RS to promptly transmit an acknowledgment signal back to the TS to indicate whether the packet transmission was successful (ACK) or not (NACK). It is well known that H-ARQ protocols may provide significant gains when operating packet data channels.
Problems Associated with to the Present Rev0 and RevA HRPD Systems
The 1xEV-DO Rev0 and RevA HRPD systems cited above may be referred to as “1x” systems, because they only support a single 1.25 MHz carrier. The 3GPP2 is currently developing standards for an evolved HRPD system that will be capable of supporting multiple carriers. The evolved HRPD system, sometimes referred to as an NxEV-DO system, and referred to herein as an “HRPD RevB” or “Nx HRPD” system (as contrasted with the HRPD RevA system defined by the above-incorporated 1xEV-DO RevA HRPD standard), can operate using multiple carriers, each occupying a different frequency spectrum (e.g., a number “N” of 1.25 MHz carriers). The HRPD RevB system is therefore referred to as an “Nx system” to indicate that it supports multiple different-frequency carriers. Presently, the 3GPP2 is defining the RevB system to support between 1 and 15 1.25 MHz carriers. When a RevB system (also referred to as an “NxDO” system) device is operated in an N=1 (i.e., “1x”) mode, it defaults to RevA functionality (i.e., it must be compatible with the above-incorporated RevA HRPD standards).
One of the benefits provided by the HRPD RevB Nx systems is an ability to process forward links and/or reverse links on each of N carriers and, as a result, increase system peak data rates by a factor of “N”. Additional benefits provided by the Nx HRPD systems are made possible, for example, due to the operations of the Nx scheduler. In Nx HRPD systems, the scheduler can be used to exploit frequency selectivity, relative carrier loading, etc. The Nx scheduler can schedule an optimal data rate/user on each of the supported carriers and, as a consequence, increase overall system throughput, decrease latency for a particular application, and improve overall user experience.
However, the benefits provided by the Nx HRPD (also referred to herein as HRPD RevB) systems come at some cost. In general, system complexity and costs increase with an increase in the number “N” of carriers supported by the HRPD RevB systems. More specifically, the Access Terminal (AT) becomes increasingly more complex and costly as “N” increases. This increase in system complexity grows more or less linearly with the number of carriers “N” supported by the system.
Therefore, a need exists for a method and apparatus providing Nx carrier support without incurring all the burdens of complexity and cost that are presently entailed by such Nx carrier support. Such a method or apparatus should allow specific 3G applications and services to benefit from the features and functions permitted by Nx HRPD systems, yet permit implementation using multi-carrier wireless communication system Access Terminals (ATs) that have reduced hardware requirements compared to present solutions. Such multi-carrier communication system ATs should ideally be relatively inexpensive to manufacture, yet permit flexible, reconfigurable operation to make efficient use of the hardware resources provided in the ATs.
The methods and apparatus described herein address the above-described problems and goals, and alleviate other difficulties as well.